The upgradation work on three sewage treatment plants (STP) in Chandigarh is targeted to be completed by September 2023. About 15 to 20 per cent of the construction work has been completed on the projects. The first project involves rehabilitation and upgradation of existing 30 million gallons per day (mgd) capacity STP at Diggian, sector 66 of SAS Nagar at an estimated cost of Rs 2.8 billion. It is being implemented by Larsen & Toubro Limited. The second project involves rehabilitation/upgradation of existing 5 mgd and 2 mgd STP at Raipur Kalan and Raipur Khurd respectively at an estimated cost of Rs 1.23 billion. It is being implemented by GSJ Environment Limited. The third project involved rehabilitation/upgradation of existing 11 mgd and 1.65 mgd STP at 3 BRD and Dhanas respectively at an estimated cost of Rs 0.74 billion. The projects are being implemented on a design, build and operate basis under public private partnership model with one-year defect liability period and operation and maintenance for a period of 15 years.